Currently, x86, Riscv, Loongarch use the Generic Entry which makes
maintainers' work easier and codes more elegant. arm64 has already
successfully switched to the Generic IRQ Entry in commit
b3cf07851b6c ("arm64: entry: Switch to generic IRQ entry"), it is
time to completely convert arm64 to Generic Entry.

The goal is to bring arm64 in line with other architectures that already
use the generic entry infrastructure, reducing duplicated code and
making it easier to share future changes in entry/exit paths, such as
"Syscall User Dispatch" and RSEQ optimizations.

This patch set is rebased on v7.0-rc3. And the performance
benchmarks results on qemu-kvm are below:

perf bench syscall usec/op (-ve is improvement)

| Syscall | Base        | Generic Entry | change % |
| ------- | ----------- | ------------- | -------- |
| basic   | 0.123997    | 0.120872      | -2.57    |
| execve  | 512.1173    | 504.9966      | -1.52    |
| fork    | 114.1144    | 113.2301      | -1.06    |
| getpgid | 0.120182    | 0.121245      | +0.9     |

perf bench syscall ops/sec (+ve is improvement)

| Syscall | Base     | Generic Entry| change % |
| ------- | -------- | ------------ | -------- |
| basic   | 8064712  | 8273212      | +2.48    |
| execve  | 1952     | 1980         | +1.52    |
| fork    | 8763     | 8832         | +1.06    |
| getpgid | 8320704  | 8247810      | -0.9     |

Therefore, the syscall performance variation ranges from a 1% regression
to a 2.5% improvement.

It was tested ok with following test cases on QEMU virt platform:
 - Stress-ng CPU stress test.
 - Hackbench stress test.
 - "sud" selftest testcase.
 - get_set_sud, get_syscall_info, set_syscall_info, peeksiginfo
   in tools/testing/selftests/ptrace.
 - breakpoint_test_arm64 in selftests/breakpoints.
 - syscall-abi and ptrace in tools/testing/selftests/arm64/abi
 - fp-ptrace, sve-ptrace, za-ptrace in selftests/arm64/fp.
 - vdso_test_getrandom in tools/testing/selftests/vDSO
 - Strace tests.
 - slice_test for rseq optimizations.

The test QEMU configuration is as follows:

	qemu-system-aarch64 \
		-M virt \
		-enable-kvm \
		-cpu host \
		-kernel Image \
		-smp 8 \
		-m 512m \
		-nographic \
		-no-reboot \
		-device virtio-rng-pci \
		-append "root=/dev/vda rw console=ttyAMA0 kgdboc=ttyAMA0,115200 \
			earlycon preempt=voluntary irqchip.gicv3_pseudo_nmi=1 audit=1" \
		-drive if=none,file=images/rootfs.ext4,format=raw,id=hd0 \
		-device virtio-blk-device,drive=hd0 \

Changes in v13 resend:
- Fix exit_to_user_mode_prepare_legacy() issues.
- Also move TIF_SINGLESTEP to generic TIF infrastructure for loongarch.
- Use generic TIF bits for arm64 and moving TIF_SINGLESTEP to
  generic TIF for related architectures separately.
- Refactor syscall_trace_enter/exit() to accept flags and Use syscall_get_nr()
  helper separately.
- Tested with slice_test for rseq optimizations.
- Add acked-by.
- Link to v13: https://lore.kernel.org/all/20260313094738.3985794-1-ruanjinjie@huawei.com/

Changes in v13:
- Rebased on v7.0-rc3, so drop the firt applied arm64 patch.
- Use generic TIF bits to enables RSEQ optimization.
- Update most of the commit message to make it more clear.
- Link to v12: https://lore.kernel.org/all/20260203133728.848283-1-ruanjinjie@huawei.com/

Changes in v12:
- Rebased on "sched/core", so remove the four generic entry patches.
- Move "Expand secure_computing() in place" and
  "Use syscall_get_arguments() helper" patch forward, which will group all
  non-functional cleanups at the front.
- Adjust the explanation for moving rseq_syscall() before
  audit_syscall_exit().
- Link to v11: https://lore.kernel.org/all/20260128031934.3906955-1-ruanjinjie@huawei.com/

Changes in v11:
- Remove unused syscall in syscall_trace_enter().
- Update and provide a detailed explanation of the differences after
  moving rseq_syscall() before audit_syscall_exit().
- Rebased on arm64 (for-next/entry), and remove the first applied 3 patchs.
- syscall_exit_to_user_mode_work() for arch reuse instead of adding
  new syscall_exit_to_user_mode_work_prepare() helper.
- Link to v10: https://lore.kernel.org/all/20251222114737.1334364-1-ruanjinjie@huawei.com/

Changes in v10:
- Rebased on v6.19-rc1, rename syscall_exit_to_user_mode_prepare() to
  syscall_exit_to_user_mode_work_prepare() to avoid conflict.
- Also inline syscall_trace_enter().
- Support aarch64 for sud_benchmark.
- Update and correct the commit message.
- Add Reviewed-by.
- Link to v9: https://lore.kernel.org/all/20251204082123.2792067-1-ruanjinjie@huawei.com/

Changes in v9:
- Move "Return early for ptrace_report_syscall_entry() error" patch ahead
  to make it not introduce a regression.
- Not check _TIF_SECCOMP/SYSCALL_EMU for syscall_exit_work() in
  a separate patch.
- Do not report_syscall_exit() for PTRACE_SYSEMU_SINGLESTEP in a separate
  patch.
- Add two performance patch to improve the arm64 performance.
- Add Reviewed-by.
- Link to v8: https://lore.kernel.org/all/20251126071446.3234218-1-ruanjinjie@huawei.com/

Changes in v8:
- Rename "report_syscall_enter()" to "report_syscall_entry()".
- Add ptrace_save_reg() to avoid duplication.
- Remove unused _TIF_WORK_MASK in a standalone patch.
- Align syscall_trace_enter() return value with the generic version.
- Use "scno" instead of regs->syscallno in el0_svc_common().
- Move rseq_syscall() ahead in a standalone patch to clarify it clearly.
- Rename "syscall_trace_exit()" to "syscall_exit_work()".
- Keep the goto in el0_svc_common().
- No argument was passed to __secure_computing() and check -1 not -1L.
- Remove "Add has_syscall_work() helper" patch.
- Move "Add syscall_exit_to_user_mode_prepare() helper" patch later.
- Add miss header for asm/entry-common.h.
- Update the implementation of arch_syscall_is_vdso_sigreturn().
- Add "ARCH_SYSCALL_WORK_EXIT" to be defined as "SECCOMP | SYSCALL_EMU"
  to keep the behaviour unchanged.
- Add more testcases test.
- Add Reviewed-by.
- Update the commit message.
- Link to v7: https://lore.kernel.org/all/20251117133048.53182-1-ruanjinjie@huawei.com/

Jinjie Ruan (13):
  arm64/ptrace: Refactor syscall_trace_enter/exit() to accept flags
    parameter
  arm64/ptrace: Use syscall_get_nr() helper for syscall_trace_enter()
  arm64/ptrace: Expand secure_computing() in place
  arm64/ptrace: Use syscall_get_arguments() helper for audit
  arm64: ptrace: Move rseq_syscall() before audit_syscall_exit()
  arm64: syscall: Introduce syscall_exit_to_user_mode_work()
  arm64/ptrace: Define and use _TIF_SYSCALL_EXIT_WORK
  arm64/ptrace: Skip syscall exit reporting for PTRACE_SYSEMU_SINGLESTEP
  arm64: entry: Convert to generic entry
  arm64: Inline el0_svc_common()
  s390: Rename TIF_SINGLE_STEP to TIF_SINGLESTEP
  asm-generic: Move TIF_SINGLESTEP to generic TIF bits
  arm64: Use generic TIF bits for common thread flags

kemal (1):
  selftests: sud_test: Support aarch64

 arch/arm64/Kconfig                            |   3 +-
 arch/arm64/include/asm/entry-common.h         |  76 ++++++++++++
 arch/arm64/include/asm/syscall.h              |  19 ++-
 arch/arm64/include/asm/thread_info.h          |  76 ++++--------
 arch/arm64/kernel/debug-monitors.c            |   7 ++
 arch/arm64/kernel/entry-common.c              |  25 +++-
 arch/arm64/kernel/ptrace.c                    | 115 ------------------
 arch/arm64/kernel/signal.c                    |   2 +-
 arch/arm64/kernel/syscall.c                   |  29 ++---
 arch/loongarch/include/asm/thread_info.h      |  11 +-
 arch/s390/include/asm/thread_info.h           |   7 +-
 arch/s390/kernel/process.c                    |   2 +-
 arch/s390/kernel/ptrace.c                     |  20 +--
 arch/s390/kernel/signal.c                     |   6 +-
 arch/x86/include/asm/thread_info.h            |   6 +-
 include/asm-generic/thread_info_tif.h         |   5 +
 include/linux/irq-entry-common.h              |   8 --
 include/linux/rseq_entry.h                    |  18 ---
 .../syscall_user_dispatch/sud_benchmark.c     |   2 +-
 .../syscall_user_dispatch/sud_test.c          |   4 +
 20 files changed, 191 insertions(+), 250 deletions(-)

-- 
2.34.1

On Tue, Mar 17, 2026 at 9:20 AM Jinjie Ruan <ruanjinjie@huawei.com> wrote:

> Currently, x86, Riscv, Loongarch use the Generic Entry which makes
> maintainers' work easier and codes more elegant. arm64 has already
> successfully switched to the Generic IRQ Entry in commit
> b3cf07851b6c ("arm64: entry: Switch to generic IRQ entry"), it is
> time to completely convert arm64 to Generic Entry.

Looks good to me, except patch 14 that needs your Signoff.

Perhaps it is best if patches 1 thru 11 are applied separately
to the arm64 tree and the remaining patches either postponed
to the next kernel cycle or applied on top of an immutable branch
based off v7.0-rc1 from the arm64 tree?

Yours,
Linus Walleij

On 2026/3/19 22:35, Linus Walleij wrote:
> On Tue, Mar 17, 2026 at 9:20 AM Jinjie Ruan <ruanjinjie@huawei.com> wrote:
> 
>> Currently, x86, Riscv, Loongarch use the Generic Entry which makes
>> maintainers' work easier and codes more elegant. arm64 has already
>> successfully switched to the Generic IRQ Entry in commit
>> b3cf07851b6c ("arm64: entry: Switch to generic IRQ entry"), it is
>> time to completely convert arm64 to Generic Entry.
> 
> Looks good to me, except patch 14 that needs your Signoff.
> 
> Perhaps it is best if patches 1 thru 11 are applied separately
> to the arm64 tree and the remaining patches either postponed
> to the next kernel cycle or applied on top of an immutable branch
> based off v7.0-rc1 from the arm64 tree?

Thanks for the review and the suggestion on the merge strategy.

1. Regarding the Split: I agree with applying Patches 1-10 to the arm64
tree first. These are foundational and ready for inclusion.

2. Regarding Patches 11-14: I am fine with postponing them or using an
immutable branch based on v7.0-rc1.


> 
> Yours,
> Linus Walleij
> 

This series looks good to me.

Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>

> Currently, x86, Riscv, Loongarch use the Generic Entry which makes
> maintainers' work easier and codes more elegant. arm64 has already
> successfully switched to the Generic IRQ Entry in commit
> b3cf07851b6c ("arm64: entry: Switch to generic IRQ entry"), it is
> time to completely convert arm64 to Generic Entry.
>
> The goal is to bring arm64 in line with other architectures that already
> use the generic entry infrastructure, reducing duplicated code and
> making it easier to share future changes in entry/exit paths, such as
> "Syscall User Dispatch" and RSEQ optimizations.
>
> This patch set is rebased on v7.0-rc3. And the performance
> benchmarks results on qemu-kvm are below:
>
> perf bench syscall usec/op (-ve is improvement)
>
> | Syscall | Base        | Generic Entry | change % |
> | ------- | ----------- | ------------- | -------- |
> | basic   | 0.123997    | 0.120872      | -2.57    |
> | execve  | 512.1173    | 504.9966      | -1.52    |
> | fork    | 114.1144    | 113.2301      | -1.06    |
> | getpgid | 0.120182    | 0.121245      | +0.9     |
>
> perf bench syscall ops/sec (+ve is improvement)
>
> | Syscall | Base     | Generic Entry| change % |
> | ------- | -------- | ------------ | -------- |
> | basic   | 8064712  | 8273212      | +2.48    |
> | execve  | 1952     | 1980         | +1.52    |
> | fork    | 8763     | 8832         | +1.06    |
> | getpgid | 8320704  | 8247810      | -0.9     |
>
> Therefore, the syscall performance variation ranges from a 1% regression
> to a 2.5% improvement.
>
> It was tested ok with following test cases on QEMU virt platform:
>  - Stress-ng CPU stress test.
>  - Hackbench stress test.
>  - "sud" selftest testcase.
>  - get_set_sud, get_syscall_info, set_syscall_info, peeksiginfo
>    in tools/testing/selftests/ptrace.
>  - breakpoint_test_arm64 in selftests/breakpoints.
>  - syscall-abi and ptrace in tools/testing/selftests/arm64/abi
>  - fp-ptrace, sve-ptrace, za-ptrace in selftests/arm64/fp.
>  - vdso_test_getrandom in tools/testing/selftests/vDSO
>  - Strace tests.
>  - slice_test for rseq optimizations.
>
> The test QEMU configuration is as follows:
>
> 	qemu-system-aarch64 \
> 		-M virt \
> 		-enable-kvm \
> 		-cpu host \
> 		-kernel Image \
> 		-smp 8 \
> 		-m 512m \
> 		-nographic \
> 		-no-reboot \
> 		-device virtio-rng-pci \
> 		-append "root=/dev/vda rw console=ttyAMA0 kgdboc=ttyAMA0,115200 \
> 			earlycon preempt=voluntary irqchip.gicv3_pseudo_nmi=1 audit=1" \
> 		-drive if=none,file=images/rootfs.ext4,format=raw,id=hd0 \
> 		-device virtio-blk-device,drive=hd0 \
>
> Changes in v13 resend:
> - Fix exit_to_user_mode_prepare_legacy() issues.
> - Also move TIF_SINGLESTEP to generic TIF infrastructure for loongarch.
> - Use generic TIF bits for arm64 and moving TIF_SINGLESTEP to
>   generic TIF for related architectures separately.
> - Refactor syscall_trace_enter/exit() to accept flags and Use syscall_get_nr()
>   helper separately.
> - Tested with slice_test for rseq optimizations.
> - Add acked-by.
> - Link to v13: https://lore.kernel.org/all/20260313094738.3985794-1-ruanjinjie@huawei.com/
>
> Changes in v13:
> - Rebased on v7.0-rc3, so drop the firt applied arm64 patch.
> - Use generic TIF bits to enables RSEQ optimization.
> - Update most of the commit message to make it more clear.
> - Link to v12: https://lore.kernel.org/all/20260203133728.848283-1-ruanjinjie@huawei.com/
>
> Changes in v12:
> - Rebased on "sched/core", so remove the four generic entry patches.
> - Move "Expand secure_computing() in place" and
>   "Use syscall_get_arguments() helper" patch forward, which will group all
>   non-functional cleanups at the front.
> - Adjust the explanation for moving rseq_syscall() before
>   audit_syscall_exit().
> - Link to v11: https://lore.kernel.org/all/20260128031934.3906955-1-ruanjinjie@huawei.com/
>
> Changes in v11:
> - Remove unused syscall in syscall_trace_enter().
> - Update and provide a detailed explanation of the differences after
>   moving rseq_syscall() before audit_syscall_exit().
> - Rebased on arm64 (for-next/entry), and remove the first applied 3 patchs.
> - syscall_exit_to_user_mode_work() for arch reuse instead of adding
>   new syscall_exit_to_user_mode_work_prepare() helper.
> - Link to v10: https://lore.kernel.org/all/20251222114737.1334364-1-ruanjinjie@huawei.com/
>
> Changes in v10:
> - Rebased on v6.19-rc1, rename syscall_exit_to_user_mode_prepare() to
>   syscall_exit_to_user_mode_work_prepare() to avoid conflict.
> - Also inline syscall_trace_enter().
> - Support aarch64 for sud_benchmark.
> - Update and correct the commit message.
> - Add Reviewed-by.
> - Link to v9: https://lore.kernel.org/all/20251204082123.2792067-1-ruanjinjie@huawei.com/
>
> Changes in v9:
> - Move "Return early for ptrace_report_syscall_entry() error" patch ahead
>   to make it not introduce a regression.
> - Not check _TIF_SECCOMP/SYSCALL_EMU for syscall_exit_work() in
>   a separate patch.
> - Do not report_syscall_exit() for PTRACE_SYSEMU_SINGLESTEP in a separate
>   patch.
> - Add two performance patch to improve the arm64 performance.
> - Add Reviewed-by.
> - Link to v8: https://lore.kernel.org/all/20251126071446.3234218-1-ruanjinjie@huawei.com/
>
> Changes in v8:
> - Rename "report_syscall_enter()" to "report_syscall_entry()".
> - Add ptrace_save_reg() to avoid duplication.
> - Remove unused _TIF_WORK_MASK in a standalone patch.
> - Align syscall_trace_enter() return value with the generic version.
> - Use "scno" instead of regs->syscallno in el0_svc_common().
> - Move rseq_syscall() ahead in a standalone patch to clarify it clearly.
> - Rename "syscall_trace_exit()" to "syscall_exit_work()".
> - Keep the goto in el0_svc_common().
> - No argument was passed to __secure_computing() and check -1 not -1L.
> - Remove "Add has_syscall_work() helper" patch.
> - Move "Add syscall_exit_to_user_mode_prepare() helper" patch later.
> - Add miss header for asm/entry-common.h.
> - Update the implementation of arch_syscall_is_vdso_sigreturn().
> - Add "ARCH_SYSCALL_WORK_EXIT" to be defined as "SECCOMP | SYSCALL_EMU"
>   to keep the behaviour unchanged.
> - Add more testcases test.
> - Add Reviewed-by.
> - Update the commit message.
> - Link to v7: https://lore.kernel.org/all/20251117133048.53182-1-ruanjinjie@huawei.com/
>
> Jinjie Ruan (13):
>   arm64/ptrace: Refactor syscall_trace_enter/exit() to accept flags
>     parameter
>   arm64/ptrace: Use syscall_get_nr() helper for syscall_trace_enter()
>   arm64/ptrace: Expand secure_computing() in place
>   arm64/ptrace: Use syscall_get_arguments() helper for audit
>   arm64: ptrace: Move rseq_syscall() before audit_syscall_exit()
>   arm64: syscall: Introduce syscall_exit_to_user_mode_work()
>   arm64/ptrace: Define and use _TIF_SYSCALL_EXIT_WORK
>   arm64/ptrace: Skip syscall exit reporting for PTRACE_SYSEMU_SINGLESTEP
>   arm64: entry: Convert to generic entry
>   arm64: Inline el0_svc_common()
>   s390: Rename TIF_SINGLE_STEP to TIF_SINGLESTEP
>   asm-generic: Move TIF_SINGLESTEP to generic TIF bits
>   arm64: Use generic TIF bits for common thread flags
>
> kemal (1):
>   selftests: sud_test: Support aarch64
>
>  arch/arm64/Kconfig                            |   3 +-
>  arch/arm64/include/asm/entry-common.h         |  76 ++++++++++++
>  arch/arm64/include/asm/syscall.h              |  19 ++-
>  arch/arm64/include/asm/thread_info.h          |  76 ++++--------
>  arch/arm64/kernel/debug-monitors.c            |   7 ++
>  arch/arm64/kernel/entry-common.c              |  25 +++-
>  arch/arm64/kernel/ptrace.c                    | 115 ------------------
>  arch/arm64/kernel/signal.c                    |   2 +-
>  arch/arm64/kernel/syscall.c                   |  29 ++---
>  arch/loongarch/include/asm/thread_info.h      |  11 +-
>  arch/s390/include/asm/thread_info.h           |   7 +-
>  arch/s390/kernel/process.c                    |   2 +-
>  arch/s390/kernel/ptrace.c                     |  20 +--
>  arch/s390/kernel/signal.c                     |   6 +-
>  arch/x86/include/asm/thread_info.h            |   6 +-
>  include/asm-generic/thread_info_tif.h         |   5 +
>  include/linux/irq-entry-common.h              |   8 --
>  include/linux/rseq_entry.h                    |  18 ---
>  .../syscall_user_dispatch/sud_benchmark.c     |   2 +-
>  .../syscall_user_dispatch/sud_test.c          |   4 +
>  20 files changed, 191 insertions(+), 250 deletions(-)
>
> --
> 2.34.1
>
>

--
Sincerely,
Yeoreum Yun